Irrigation systems such as center pivot and linear irrigation systems have a number of drive trains each comprising a drive motor and a wheel drive gearbox. The drive motors are susceptible to overheating and overdrawing electric current. Each drive motor typically has a motor protector for opening its electrical circuit when it starts to get too hot or begins drawing too much current. This prevents further damage to the drive motor but often results in significant irrigation system down time until the drive motor is fixed or replaced.
The wheel drive gearboxes are also susceptible to overheating. Lubricants in the wheel drive gearboxes lose viscosity when their temperatures rise, resulting in deterioration of their moving parts. This further raises the temperature of the lubricants in a runaway effect, which can lead to failure of the wheel drive gearboxes. The extra resistance of an overheated wheel drive gearbox also puts extra strain on the drive motor, thus exacerbating drive motor overheating. Furthermore, overheating of a wheel drive gearbox is often not discovered until it fails, which can damage the drive motor and other components and often results in significant irrigation system down time until the wheel drive gearbox, drive motor, and other affected components are fixed or replaced.
Irrigation drive train components may also heat up too quickly or increase current draw too quickly without exceeding temperature or current draw thresholds. Since irrigation control systems typically only monitor drive motor temperatures and current draw, some drive train problems go undetected until the affected part is damaged or fails.
Irrigation drive train performance complications, such as overheating and overdrawing electric current, can be caused by a number of factors including large diameter tires, higher speed output motors, variable frequency drives, terrain, rutting (intentional or unintentional), and aging drive train components. These factors are not typically tracked, which often results in less than optimal solutions being employed during maintenance. For example, a short rut causing a drive motor to temporarily overheat may result in an unnecessary motor replacement and unnecessary irrigation system down time. A failing wheel drive gearbox may cause its drive motor to overheat, resulting in the drive motor and not the wheel drive gearbox being replaced.